Lymphocyte Aggregation in Low-Grade B-Cell Lymphoma

Platelet and erythrocyte agglutination is known to happen in vitro due to EDTA or temperature-induced cold antibodies. Leukocyte agglutination is far less common, and its etiology is not always known. The 2 cases presented herein are of low-grade B-cell lymphomas consistent with splenic marginal-zone lymphoma that presented with lymphocyte agglutination. In Case A, the lymphocyte aggregates were not resolved by warming the sample or by non-EDTA anticoagulation. In Case B, the lymphocyte aggregates were largely resolved by warming the specimen at 37°C for 15 minutes. The 2 cases presented herein further show that the etiology of lymphocyte aggregation can have multiple causes, even within the same disease process.